Apple iPhone 4s and Apple iPhone 4If you plan on hocking your old iPhone when the new when hits in September, you may want to consider going through Gazelle before posting on Craigslist. The service is letting sellers get today's price quote locked-in, and it'll last until Oct. 1. That means you don't have to go phoneless; you can essentially keep your device until you pick up the new one on Sept. 21.

The only stipulation attached is that you have to get your quote before August 31; anything beyond that won't be honored. Indecisive folks won't have to go through with Gazelle's offer should they decide against Apple's new iPhone, which is yet another reason to lock your price in now.

Gazelle is currently offering $277 for a 16GB iPhone 4S in "good" condition, but Anthony Scarsella Gazelle's chief gadget officer warns that price could depreciate by $100 by the end of September.

"We're buying so many phones and it floods the market," Scarsella said. "That tends to drop pricing."

I've had great success with Craigslist, so I'd personally go with that option. But Gazelle's extension to the beginning of October is a great way to hang onto your device until you get a new one, meaning you don't have to experience the Dark Ages for the three or so weeks.

[via CNET]